Sarah Gardner: We all know the key role social media played in the push toward freedom in the Arab Spring. Now, some people are wondering about another effect of social media -- concerns that an anti-Muslim video on YouTube helped whip up attacks on U.S. embassies in Egypt and Libya. Four U.S. officials were killed today in Benghazi.

We should note, there are now reports suggesting that the attack in Libya was planned, and not the result of an angry mob.

But the video does raise questions about YouTube, freedom of speech and corporate ethics. Our New York bureau chief Heidi Moore reports.

Heidi Moore: YouTube is best known for Justin Bieber and cat videos. But now it's wrapped up in foreign policy.

Jonathan Turley is a professor at the George Washington University Law School. He told his students today: YouTube didn't cause unrest in the Middle East.

Jonathan Turley: People suggest that these murders were caused by a film. They weren't caused by a film. The anger was certainly caused by a film. But that's no excuse to engage in murder.

It also may not be YouTube's problem. YouTube built its business on being a forum for free speech. Yochai Benkler is a professor at Harvard Law School.

Yochai Benkler: We have to be careful that the concern over the violence doesn't lead us to give up that anybody can communicate with anybody else from anywhere to anywhere.

Jonathan Zittrain: They may be more like the phone company.

Jonathan Zittrain co-founded the Berkman Center for Internet and Society. He says YouTube is much more like a utility than a publishing company.

Zittrain: People don't turn around and say to Verizon, 'what are you doing providing phone service to mobsters and unsavory people?'

And what about the bottom line? You can find this same video on YouTube under a bunch of different names. Some of them have ads. But the way ads work on YouTube is that you can choose to sponsor a particular video or let an algorithm pick for you. Jeff Jarvis wrote “What Would Google Do?”

Jeff Jarvis: It’s not like the advertiser is choosing to buy Seinfeld. They’re buying ad availability on YouTube.

A YouTube spokesman says the video doesn’t break the company’s rules, so it will stay up. But it has imposed restricted access in Egypt and Libya. Call it YouTube Diplomacy.